GM-64Geology
and coal resources of Vanderwagen quadrangle, McKinley County, New
Mexico

Vanderwagen 7½-min
quadrangle is in the southern part of the Zuni Basin in southwest McKinley
County approximately 15 mi south of Gallup. Elevations range from lows of
approximately 6,650 ft in the Manuelito Canyon in the northwest part of
the quadrangle and of approximately 6,800 ft where Whitewater Arroyo crosses
the Piñon Springs anticline in the southwest corner of the quadrangle
(type locality of the Whitewater Arroyo Tongue of the Mancos Shale) to a
high of 7,283 ft in the northeast corner. Middle Jurassic (Zuni Sandstone)
through Tertiary (Bidahochi Formation) units exposed in the quadrangle dip
gently 1° 4º to the northeast toward the center of the Zuni
Basin. Most of the outcrops, however, are Upper Cretaceous rocks of the
Dakota-Mancos sequence and the coal-bearing Gallup Sandstone and Crevasse
Canyon Formation. Quaternary eolian sand and alluvial deposits of sand,
silt, and clay blanket much of the older strata. GM-64 includes detailed
discussions of the coal resources, regional stratigraphy, and regional relationship
between the Gallup Sandstone and the Tres Hermanos Formation, one cross
section, and 15 map-unit descriptions. This is a companion to GMs 65 and
66.